Volume 112, Issue 19, 15 May 2000
Index of content:
112(2000); http://dx.doi.org/10.1063/1.481426View Description Hide Description
The rate of the chemiluminescent reaction is greatly enhanced inside cold (0.38 K) helium droplets. If Xe atoms are added to the droplets, the “hot” surface channel is suppressed and all the emission is in a vibrational progression of sharp lines, indicating that the reaction occurs only inside the droplets.
112(2000); http://dx.doi.org/10.1063/1.481476View Description Hide Description
An extremely large isotope effect has been measured in the dissociativechemisorption of nitrogen molecules over Ru(001). It varies from unity at kinetic energies above 2 eV to 0.2 at eV. These observations are consistent with a barrier for direct dissociation of 1.8 eV, in agreement with previous experiments and recent ab initiodensity functional theory calculations. It supports earlier studies that proposed tunneling as the dissociation dynamics mechanism.
112(2000); http://dx.doi.org/10.1063/1.481427View Description Hide Description
Molecular dynamics simulations of united atom nonentangled linear polyethylene models were utilized in order to systematically examine local orientational dynamics. In agreement with recent experiments and theoretical predictions, slow relaxation processes associated with motions of length scale of the order of chain dimensions are identified and analyzed with a method that allowed a model-free determination of their relative contribution to local orientational relaxation. Factors of intra- and intermolecular nature affecting their characteristics are discussed as well.
112(2000); http://dx.doi.org/10.1063/1.481428View Description Hide Description
Regarding the solvation of molecules to water, the adsorption of molecules on the water surface has mostly been considered. Here we provide spectroscopic evidence for the adsorption and solvation behavior of ammonia on the ultra thin ice film surface formed on Ru(001) by the use of infrared reflection absorption and thermal desorptionspectroscopies. Here we prove that the solvation of ammonia involves two steps. They are the hydrogen bondadsorption and the transfer into bulk. The hydrogen bonding adsorbed ammonia on ultra thin ice film in a form is evidenced for the first time. Upon heating, bulk transfer upon a conversion to a form is observed for this hydrogen bonded species, however it is not for bilayer and multilayer species. © 2000 American Institute of Physics.